• W.J. Corbett, A.S. Fisher
  SLAC, Menlo Park, California
• W.X. Cheng
  BNL, Upton, Long Island, New York
• W.Y. Mok
  Life Imaging Technology, Palo Alto, California

For top-up injection it is important to understand the time evolution of the incident charge in the transverse and longitudinal coordinate systems. In SPEAR3, the injection system has a vertically-deflecting Lambertson septum with the injected beam entering ~13mm to the inside. The resulting large-amplitude betatron oscillations give rise to rapid filamentation followed by nominal radiation damping and in some cases non-linear x-y coupling. Similarly, in the longitudinal dimension, a mis-match in beam arrival time or energy can result non-linear beam dynamics and damped synchrotron motion. To the next order, any betatron, bunch length or energy spread mismatch will generate damped ‘quadrupole’ oscillations or even higher-order motion. In this paper we report on measurements of injection beam dynamics in the transverse and longitudinal coordinate systems using a fast-gated, image-intensified CCD camera and a Hamamatsu C5680 streak camera, respectively. The injection beam dynamics are shown to contain relatively complicated evolution in the x-y-z beam distributions that change with injection conditions and storage ring lattice configuration.

• W.X. Cheng
  BNL, Upton, Long Island, New York

A diffraction-limited storage ring like NSLS2 sets more stringent beam stability requirements. Due to resistive wall impedance and fast-ion effect, transverse instabilities will happen at low current (~15 mA). An active transverse feedback system has been designed to cure the betatron oscillations. The system will have a <200 us damping rate at 50 0mA to suppress the fast-ion instability, which is severe in the vertical plane due to small beam size.

• W.X. Cheng
  BNL, Upton, Long Island, New York

A synchrotron light diagnostic beamline has been designed at the NSLS-II storage ring, using the dipole radiations. A "cold-finger" configuration has been selected to block the central x-rays. Beam power on the first mirror is less than 1 W, so no water cooling was required for this in-vacuum mirrors. The beamline layout and major applications will be discussed in this paper. Two vacuum ports are reserved in the NSLS2 booster ring to monitor the transverse profile as well as bunch length measurement during ramping. There will be a synchrotron light port in the BTS transport line for observing the injecting beam behavior during top-up operation.